Here's Some Important Durability Factors

Galvanized Mesh Fencing

When you are planning to erect a galvanized mesh fence you need to make sure that you have the right product for the job. Fortunately, Protective Fencing manufacture and stock a wide range of galvanized steel mesh and welded wire mesh products including:

In order to choose the right product for your project you need to take into account not only the human or animal elements that you wish to control such as preventing stock, human intrusion or health and safety issues but also the climatic elements that will affect the longevity of your fence.

And the principle concern here is corrosion. This is the formidable, silent enemy of all things metallic because, as Neil Young tells us, ‘rust never sleeps’.

What standards govern the galvanized steel process?

Australia and New Zealand are well armed with standards that outline the appropriate use of steel and the ideal galvanizing process for those critical fencing areas. It is important that you build your fence in accordance with these guidelines and so you either need to spend some time understanding the requirements or seek expert advice.

If you fail to do this you may end up with fencing that is subject to premature failure leaving you liable to expensive replacement costs, security and animal control issues, and even prosecution under health and safety legislation.

An understanding of the AS & AS/NZS standards, in particular the AS/NZS 2312.2 Guide to the protection of structural steel against atmospheric corrosion by the use of protective coatings – Part 2: Hot dip galvanizing, AS/NZS 4680, and AS 4312 is pivotal here. These three standards cover the design, durability, and manufacturing processes involved in the manufacture of galvanized steel mesh products.

Fortunately, recent revisions have made the standards considerably easier to follow so let’s look at some of the key elements that will help you choose the right product for the maximum durability of your fence.

How does galvanizing prevent corrosion?

Galvanizing protects the underlying steel in three ways:

1. By providing a physical barrier of zinc and zinc carbonate preventing corrosive substances from reacting with the underlying steel.
2. The zinc, thanks to its greater reactivity, protects the underlying metal by corroding before iron.
3. The zinc functions as a sacrificial anode so that even if the coating is scratched, the exposed steel will still be protected by the zinc cathodic reaction.

In normal conditions galvanising can provide corrosion protection for the steel core for up to 50 years, or more in arid areas. However, in rural, industrial, and marine environments pollutants including herbicides, sulphur compounds, and high salt content can rapidly increase the corrosion rate of zinc and reduce the life of the fence.

It’s important to remember that corrosion rates are also affected by a number of other factors such as rainfall, humidity, temperature, and the thickness of the zinc coating. For example, whereas heavy rainfall can increase corrosion rates in dry conditions, it can however significantly reduce corrosion rates in a highly corrosive marine or industrial environments.

Australian corrosion zones

Rust never sleeps but it is definitely more active under certain conditions and corrosion friendly conditions can significantly reduce the life of your fence.
The standard AS 4312 helpfully divides Australia into six corrosion zones: C1 very low (such as dry indoors) ranking as the least corrosive to CX (severe surf shoreline) being the most corrosive.

How long will my fence last?

Remember that a number of factors will influence the lifespan of your fence including humidity, temperature, and exposure to salts. Prevailing winds can push corrosive salt-laden air further inland as well.

However, there is a clear linear relationship between the thickness of the zinc coating and the duration before the wire mesh will require maintenance. Below are some examples (based on information from the Galvanizers Association of Australia) to express this in easy to understand terms:

• Steel with a galvanized coating thickness of 85 µm in a C2 environment will last between 30 to 50 years before maintenance is required
• Steel with a galvanized coating thickness of 85 µm in a C4 environment — 20 to 40 years before maintenance is required
• Steel with a galvanized coating thickness of 85 µm in a C5 environment — 10 to 25 years before maintenance is required
• Steel with a galvanized coating thickness of 85 µm in a C6 environment — 5 to 10 years before maintenance is required

Protective fencing can produce a wide range of galvanized steel mesh with varying wire types and surface coatings to suit every application.

Getting the best out of your fence

Galvanized steel mesh panels are some of the best fencing products available for Australia’s tough conditions; galvanizing has been protecting steel for 140 years with outstanding success. With the right product for the conditions, correctly installed and maintained, your galvanized steel fence will last for many decades.

Periodic maintenance inspections will quickly expose areas of damage that may need attention. This is particularly true where galvanized mesh panels are subject to harsh treatment or conditions.

Regular rainfall can help reduce the effects of high salt deposition or the presence of pollutants or aggressive chemicals but a regular cleaning programme may be appropriate in certain situations to prolong the life of galvanized steel sheets.

Successful fencing always starts with the right knowledge and expert advice. Come and talk to the friendly experts at Protective fencing –we are one of Australia’s leading providers of galvanized steel mesh and wire mesh products.

Updated 18/11/2016